This thesis examines feminist and queer actors emerging in highly mediated environments and the forms of political organisation and critical knowledge production they engage in. It indicates that older debates around gender and sexuality are being reformulated in digital networks and identifies alternative understandings which are being developed. The study foregrounds a performative conceptualisation and argues that political realities are produced in dynamic configurations of communication media, discourses and bodies. It suggests that network technologies constitute sources of vulnerability and anxiety for feminists and stresses the significance of registering how embodied subjectivities emerge from these experiences. To achieve its aims and to map activity happening across different spaces and scales, the project attended to context-specific processes of mediation at the intersections of online and offline settings. It employed ethnographic methods, internet visualisation, in-depth interviewing and textual analysis to produce the following key outcomes: it registered changing understandings of the political in relation to new media amongst a network of women's organisations in London; it investigated the centrality of social media and global connections in the shaping of local queer political communities in Brighton; it complicated ideas of control, labour and affect to analyse emerging sexual identities in online spaces like nofauxx.com, and offline postporn events; finally, it traced feminist actors gathering around new reproductive technologies, at the crossing fields of grassroots activism and the academy. Today, women's groups and queer activists increasingly use networked communication for mobilisation and information-sharing. In a climate of widespread scepticism towards both representational politics and traditional media, questions about the role of digital networks in enabling or limiting political engagement are being raised. This thesis aims to contribute to these debates by accounting for the ways in which feminist and queer activists in digital networks reformulate the relationship between communication media and politics.